Large-area detectors for obtaining X-ray digital images of large size are of considerable interest due to their potential use in a large number of applications, such as medicine, industry or applications related with security. The systems currently available in the market have a number of limitations in various aspects, and these involve major disadvantages.
A first limitation is based on the fact that the area of the surface for which it is possible to obtain a continuos image is generally small. This means that it is only possible to use the current devices for certain very specific applications.
A second limitation stems from the low quantum efficiency of the detectors, this being understood as the quotient between the number of photons captured by the detector in order to produce the image and the number of photons incident thereupon. The fact that said efficiency is low means that a high dose of radiation has to be supplied in order to produce a radiography. The main disadvantage of said limitation lies in excessive exposure to radiation of the individual or item of which it is wished to obtain the image or images, as such high exposure can lead to injury or harm, often irreparable.
A third limitation derives from the noise produced by the dispersed photons, which end up at any part of the image. Said noise is superimposed over that inherently found in any detector, and limits the possibility of obtaining images of objects with low contrast.